syslogd - log systems messages
syslogd [-f configfile] [-m markinterval] [-d]
Syslogd reads and logs messages into a set of files described by the
configuration file /etc/syslog.conf. Each message is one line. A
message can contain a priority code, marked by a number in angle braces
at the beginning of the line. Priorities are defined in <sys/syslog.h>.
Syslogd reads from the named pipe /dev/daemonlog, from an Internet domain
socket specified in /etc/services, and from the special device /dev/log
(to read kernel messages).
Syslogd configures when it starts up and whenever it receives a hangup
signal. Lines in the configuration file have a selector to determine the
message priorities to which the line applies and an action. The action
field are separated from the selector by one or more tabs.
Selectors are semicolon separated lists of priority specifiers. Each
priority has a facility describing the part of the system that generated
the message, a dot, and a level indicating the severity of the message.
Symbolic names may be used. An asterisk selects all facilities. All
messages of the specified level or higher (greater severity) are
selected. More than one facility may be selected using commas to
separate them. For example:
Selects all facilities at the emerg level and the mail and daemon
facilities at the crit level.
Known facilities and levels recognized by syslogd are those listed in
syslog(3) without the leading ``LOG_''. The additional facility ``mark''
has a message at priority LOG_INFO sent to it every 20 minutes (this may
be changed with the -m flag). The ``mark'' facility is not enabled by a
facility field containing an asterisk. The level ``none'' may be used to
disable a particular facility. For example,
Sends all messages except mail messages to the selected file.
The second part of each line describes where the message is to be logged
if this line is selected. There are four forms:
o A filename (beginning with a leading slash). The file will be opened
in append mode.
o A hostname preceeded by an at sign (``@''). Selected messages are
forwarded to the syslogd on the named host.
o A comma separated list of users. Selected messages are written to
those users if they are logged in.
o An asterisk. Selected messages are written to all logged-in users.
Blank lines and lines beginning with `#' are ignored.
For example, the configuration file:
logs all kernel messages and 20 minute marks onto the system console, all
notice (or higher) level messages and all mail system messages except
debug messages into the file /usr/spool/adm/syslog, and all critical
messages into /usr/adm/critical; kernel messages of error severity or
higher are forwarded to ucbarpa. All users will be informed of any
emergency messages, the users ``eric'' and ``kridle'' will be informed of
any alert messages, and the user ``ralph'' will be informed of any alert
message, or any warning message (or higher) from the authorization
The flags are:
-f Specify an alternate configuration file.
-m Select the number of minutes between mark messages.
-d Turn on debugging.
Syslogd creates the file /var/run/syslog.pid, if possible, containing a
single line with its process id. This can be used to kill or reconfigure
To bring syslogd down, it should be sent a terminate signal (e.g. kill
/etc/syslog.conf the configuration file
/var/run/syslog.pid the process id
/dev/daemonlog Name of the named pipe
/dev/log The kernel log device